What is Life? A Guide to Biology Ch. 10

Node

The point on an evolutionary tree at which species diverge from a common ancestor

Adaptive radiation

The rapid diversification of a small number of species into a much larger number of species, able to live in a wide variety of habitats.

Horizontal gene transfer

The transfer of genetic material directly from one individual to another that is not necessarily related (ex. bacteria)

Biodiversity

The variety and variability among all genes, species, and ecosystems

Genus

a classification of organisms consisting of closely related species

RNA World hypothesis

describes how the Earth may have been filled with RNA-based life before it became filled with the DNA-based life we see today

Biological species concept

Populations of organisms that interbreed or have the potential to interbreed under natural conditions and that cannot interbreed with organisms outside their group.

Reproductive isolation

Separation of species or populations so that they cannot interbreed and produce fertile offspring

Morphological species concept

Species are defined based on their physical features

Macroevolution

The accumulated effect of microevolution over a long period of time

Extinction

The complete loss of all individuals of a species

Polyploidy

The doubling of the number of sets of chromosomes in an individual

Allopatric speciation

The formation of new species in populations that are geographically isolated from one another.

Sympatric speciation

The formation of new species in populations that live in the same geographic area

Prezygotic barrier

Physical inability to mate with each other, or the inability of male sperm to fertilize

Monophyletic

A group containing all of the descendants of a common ancestor

Archaea

A group of prokaryotes that are distinct from bacteria and thrive in some of the most extreme environments

Mass extinction

A large number of species become extinct over a short period of time due to extraordinary and sudden environmental change

Microevolution

A slight change in allele frequencies over one or a few generations

Analogous trait

Arise when groups independently adapt to similar environments in similar ways

Kingdom

Below Domains. There are six kingdoms

Convergent evolution

Evolution toward similar characteristics in unrelated species

Phylogeny

Evolutionary history of a group of organisms

Speciation

Formation of new species. Phase 1 is reproductive isolation. Phase 2 is genetic divergance

Species

Natural populations of organisms that can interbreed and are reproductively isolated from other such groups. The narrowest classification in the Carolus Linnaeus classification system

Postzygotic barrier

Occur after fertilization and generally prevent the production of fertile offspring

Punctuated equilibrium

Pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change

Homologous feature

inherited from a common ancestor

Background extinction

normal extinction of various species as a result of changes in local environmental conditions